<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>登录成功</title>

    <script>

        window.onload = function f() {

            alert("三次点击后跳转到百度");
            for(var i=3;i>0;i--){
                alert(i)
                if(i==1){
                    window.location.href = "https://www.baidu.com/";
                }
            }


        }
    </script>

</head>
<body>

<p>this is my first web</p>

<input type="button" value="退出登录" id="exit" onclick="window.location='主网页.html'">

<a href="https://uland.taobao.com/">淘宝</a>

</body>
</html>